Azure hawker

Azure hawker

There are only three or four species of dragonfly in the area. This is one of the biggest at 60-65 mm.


Photo and text: Stuart Keenan

Bluethroat

Bluethroat

One of the most beautiful birds in the area, common in the birchwoods. Recent research has shown the Kilpisjärvi area to be the best place so far found for these birds with up to 50 breeding pairs per square kilometer.

Photo and text: Stuart Keenan

Thistles

Thistles

Photo: Stuart Keenan

Lichen forest

The lichens pictured here belong to the genus "cladonia" which contains a number of species important to reindeer as a primary food source .They are found in more open tundra like habitats and are extremely cold tolerant.

Cadonia lichen

Photo and text: Stuart Keenan

Hooded crow

This ex hoodie has been killed and eaten by a Perigrine Falcon usually they only leave the wings attached to the breastbone. This is the first time I've found prey remains with the legs as well.

Hooded crow remains.

Photo and text: Stuart Keenan

Lemmings

Lemmings are arctic rodents similar to voles. In Kilpisjärvi they were very plentiful this year. Our nature enthusiast Stuart managed to get quite a few very nice photographs of these creatures during his stay. Today we post the best of them.

There are many species of Lemming found around the arctic, this one is the Norweigian Lemming and this year it was very common. The population of Lemmings vary in a cycle during which they increase in number until the habitat can no longer support so many and they are forced to migrate en masse to find food. In some years the population reaches plague proportions when the ground is literally crawling with them. During these plague years large numbers of them die crossing rivers, lakes and other obstacles, which led to the myth of 'mass suicide' this myth was further enhanced by a so called wildlife documentary made in 1958 by Walt Disney in which hundreds of lemmings were captured and taken to the top of a cliff in Canada, they were then forced to run on to a revolving turntable which hurled them off the cliff thus creating the myth.

Cute lemming. Copyright Stuart Keenan.

I discovered they are not always so cute though and some would squeek loudly as I past and actually challenge me if I moved closer.

Angry lemming. Copyright Stuart Keenan.

It goes without saying that this year, there also seem to be quite a lot of young well fed owls. On my way back to Sodankylä I counted at least 15 young owls beside the road, preying for voles and lemmings that were brave enough to attempt crossing a road -- a common sight this year as well.

Calm lemming. Copyright Stuart Keenan.

At first I thought the reason for the aggressive behaviour of some lemmings might be because they were females with young nearby, but one of the biologists told me that breeding lemmings tend to be pretty quiet and its more likely to be individuals on the move, perhaps when they are on the move they are more vulnerable to predators and therefore more defensive.

Agitated lemming. Copyright Stuart Keenan.

Very agitated lemming. Copyright Stuart Keenan.

Photos and text: Stuart Keenan.

Reindeer, Part Two

Silhouette of a reindeer hiding under the HBA tiles.  

A while back, we had a post about Reindeer at the KAIRA site. This time we will post some more pictures of these animals which have found shelter under our HBA field.

At any given moment during our cabling work, there were at least two reindeer under our antenna. They arrived on the day that we accidentally brought in some salted gritting sand to fill in one of the cable trenches. At first, they were a bit shy, but on the second week they were already feeling very much at home. 

So far there haven't been any problems with the reindeer. They have been very relaxed, and have grown to be very used to the kind people who obviously are building them a huge reindeer shelter. Little do they know that we have already put up most of the fence posts for our reindeer fence, which will hopefully be in place by the time mating season starts. This is when the reindeer get more aggressive, and might pose more risk to our radar receiver. At SGO, we have previously had problems with reindeer that think various antennas are competing male reindeer with fancy antlers that just call out for a duel. Already now there is a small risk of one of these guys getting their antlers tangles up in some of the cables, even though they are fairly well protected by the cable trays and ducts. 

Reindeer breastfeeding. 

Another one hiding under the tiles.

Yet another one hiding under the tiles.

Photo credits: Mikko Orispää.

Saana

A view of KAIRA with Saana behind it.
Photo credits: Mikko Orispää.  

Saana, the landmark of Kilpisjärvi is mentioned in many of the posts on this blog already, but today we will offer several more pictures of it. It is approximately 1030 m from the sea level and approximately 500 m above the KAIRA site. It is also one of the most well known fells in Finland. Nearly every Finn would recognize it from an image from its unique steep south east slope.

Our radar has an excellent view to this fell, which is evident from the picture on the left, taken from the northern side of the field. The picture below shows Saana from the south.

Saana viewed from the south.
Photo credits: Stuart Keenan

Siilasjärvi

The Pikku-Malla fell, as seen from Siilasjärvi.
Photo credits: Mikko Orispää. 

There is a lake called Siilasjärvi several hundred meters away from the array. On this lake, the water is crystal clear, with a shallow sandy beach and a spectacular view to the neighbouring fells Saana and Pikku-Malla. On the day that we went down to the lake, there were also several young merlin on a lookout for lemmings.

A small hut storing fishing nets on the shore of Siilasjärvi.
Photo credits: Mikko Orispää.  

First light

Electrifying the RF container.

We have first light! Well, not in the conventional astronomical instrument sense no, but we have now managed to get electricity to the RF container, where all of the signal processing will be located.

The cable mausoleum has also got a roof on top of it, which will prevent any snow and ice forming in our cables. Let's hope that the mausoleum will also be rodent-proof once we get the walls on it.

Hooking up to the mains.

Doing the mausoleum roofing work. The owl nesting box can also be seen on top of the RF container.

Nightly visitors

I had been told there was a pair of hawk owls breeding somewhere near the KAIRA site, then Derek and Juha saw them one night when they were on site late, so I went along the next night to try to see them and managed to get a few photos.

On a couple of nights we had spotted several young northern hawk owls flying around the site. There was even a photograph of one of them earlier. The young birds were just learning to fly and did all kinds of silly crash landings and such while they where checking us out.

Stuart managed to get some very nice pictures on one of the nights. In Finnish these birds are called "hiiripöllö", which means mouse owl.

On his last day, Stuart even built a nesting box for the owls. Their presence will hopefully keep the small rodents from chewing on our cables.

Hawk owl sitting on top of the 3D cameras.

After warching two adults and one young flying around from perch to
perch for a while I decided to try to attract the bird on the cameras
a bit closer by making mouse noises, it worked and it came closer
to investigate.

Making the mouse noises worked well for the owls but backfired on
me the next day. At lunchbreak I went into the forest to look for the
nest site and was away a bit longer than I should have been when I
heard a strange owl in the distance, so I headed straight for it. When I
emerged from the trees I was back at the KAIRA site where I found
Derek making owl calls, the theory being mouse calls attracted
the owls for Stuart so maybe owl calls will attract Stuart back to
work. It worked like a charm and I was back at work before I knew
I had been fooled. Well done Derek

Photos: Stuart Keenan

Stuart Keenan

Stuart Keenan (pictured below) was helping us to build the KAIRA array this summer for four weeks. He has helped out with many of the international LOFAR stations too. He is also an avid nature enthusiast -- he even helped out some biologists at the Kilpisjärvi Biological station to find merlin nesting sites. During this month, we will be posting some of the nature photographs that he took during his stay in Kilpisjärvi. We will also his descriptions of the photos.

Stuart Keenan on top of Pikku-Malla with the KAIRA site seen on the background. 

For the last two years I have worked on the Installation of LOFAR stations across Europe, and this year I had the chance to join the team at Kilpisjärvi for the installation of the KAIRA / LOFAR station in north west Finland. I was exited about this for two reasons, first I love working on LOFAR and having a small part to play in this fantastic project, and second I had never been to the arctic before, so being a bit of a wildlife freak I had a chance see some species new to me. During my stay I was out at weekends, evenings and lunch breaks with my camera trying to photograph nature around the KAIRA site. Over the coming weeks you can see some of what I found. Hope you like it.

This is one four young merlins, reared in an old hooded crow's nest about 200 m from the KAIRA site.

Young merlin.

Young merlin.

Photos and text: Stuart Keenan.

LBA Topographic Survey

The coarse grained topographic survey of the LBA field was conducted
using a laser level and laser distance finder. First 10 posts were
marked on the corner points and on the center of the field. The
distances between these posts were measured using a laser distance
finder. Several distances were also cross-checked with a tape
measure. The LBA field center point, one of the corner points, and a
reference point were also measured using a Sokkia precision GPS
device. The accuracy of the measured distances between the posts was
estimated to be +/- 10 cm. The accuracy of the GPS measurements has
not yet been estimated, but by comparison with tape measure distances,
it is expected to be approximately +/- 5 cm in longitude and latitude,
but significantly higher in altitude.

In addition to the 10 posts, we added a post that marks the
approximate location of the LBA field centerpoint, as the previous
center post was too close to the reindeer fence on the outer perimeter
of the KAIRA site. This was then measured using a precision GPS with a 1
hour integration time.

The local coordinates of the posts were then determined using
triangulation. We then used a string with 10 m marks to measure the
variation of ground level at approximately 10 m intervals on the
baselines between the edge posts. The measurement points are shown in the figure below.

Based on these results, the difference between the highest and lowest
point is approximately 220 cm. The ground is fairly even over the
whole field, and the altitude drop occurs evenly over the whole
field, with a slightly steeper descent approximately half-way down the
field. The topographic map of the LBA field is shown in the figure below.

Based on several test hole that were dug in the ground, the surface
layer of organic material is 5-20 cm thick. Underneat this, is a layer
of wet silt. This is a non-Newtonian fluid (very similar to a mixture
of corn starch and water), which is hard when forced, but liquid when
gentle pressure is applied. When dried up, the material is
powder-like and easilily blown away by the wind. It is difficult to
estimate what impact this has in terms of ground movement due to
permafrost, but most likely this is not a very stable soil-type.

Cable barcodes

At the end of each signal cable, there is a barcoded label. This applies to the patch cables, the cables in the tiles and the long signal cables that go from the tiles back to the RF-container.



Each cable within the system is carefully manufactured and the serial number on the cable contains information about its performance and role. For example, the one in the middle of this photograph (CHY-1154654-2204090013) is an 'C'able from the 'H'igh-Band Array, 'Y'-polarisation. It is '115' metres long and has a delay of '4654' tenths of a nanosecond. This means that, in laboratory conditions, it takes 465.4 nanoseconds for a signal to travel down this cable.

What then follows is the date of manufacture (220409 = 22 April 2009) and the cable ID for that day (this one was number 13 for that day).

All of this information can be scanned quickly with a barcode scanner. This then forms part of the site inventory, which means it is very easy to find certain parts in the event of a fault.

Also, in order to make visual recognition easier, certain labels will be colour coded. For the array cables (of which the ones in the photograph are examples), the white labels are for the Y-polarisation and the orange labels are for the X-polarisation. This is why we colour coded the progress reports with orange and white!

LBA centre

At the conclusion of the LBA survey work (carried out by Mikko Orispää and Juha Vierinen), a centre mark was driven deep into the ground. This is the centre point of the entire LBA array and the mark on the top has been measured accurately to be sent to ASTRON for them to calculate the coordinate locations for the individual antenna elements.


The taller, thinner post to the side of the centre mark is just a snow pole. It should (just) be visible over the snow allowing us to find the mark in winter if required.

Photo: D. McKay-Bukowski

Cable mausoleum

Another photograph of the work being done on the cable mausoleum. This is the structure where the surplus cable length is zig-zagged back and forth before going into the RF-container.

Here, Pertti Nissinen (left) and Rauno Oikarainen fit the support timbers for the next level of the mausoleum. The white pipes are the ducts that go into the RF-container.

LBA survey work

Although not due until next year, the survey for the LBA (Low-Band Array) was carried out at the beginning of the month.

Juha Vierinen (far distance) and Mikko Orispää doing the survey work.

Juha Vierinen at the end of the day's work.

It's amazing to think that it is less than a year since Markku Postila and I did the same work for the HBA. That seems like an eternity ago!

Trimming

With the cabling finished, there were just a few minor adjustments to be made to the woodwork.


Here, Pertti Nissinen trims a beam to allow the final cable dressing to be done neatly.

Frog

This little frog was spotted on the LBA field at the beginning of the month, at about the time we were doing the LBA field survey.


It is amazing that these creatures survive the long Arctic winter, but one of the scientists at the Biological Research Station explained that they hibernate in the mud at the bottom of the lakes. Although the lake surfaces freeze to a thickness of over a metre, the lake bottom remains liquid thus permitting fish, frogs and other creatures to endure the harsh winter.

Photo: D. McKay-Bukowski

Reindeer

Yes, this is Lapland. And, yes, we get a lot of reindeer here. At this time of the year in particular the reindeer are out and about enjoying the abundance of food. But, for some strange reason they like to visit the KAIRA site. Every day now, we're seeing them come through the array area. Sometimes there's just a lone one or perhaps a mother and baby. Other times, there can be groups of a dozen or so.


Now if they just wandered past and kept going, that wouldn't be so bad. However, they do get up to a bit of trouble.

They certainly like to live underneath the radar. Especially in the middle of the day when it gets quite warm (over 10 celsius), they like to go under the tiles and enjoy the shade.

Then there's distracting (or intimidating!) the KAIRA staff. In the next photograph, Stuart Keenan is surrounded!

Also in the above photograph, the one on the left is eating the sand. Oh, yes... that's the other problem. They liked to eat our trench sand!

We had a large pile of sand, which were were going to use for lining the cable trenches, but the reindeer ate it. The reason for this unusual behaviour is that the sand we had was gritting sand, used in winter for the roads. As a result, there was some salt in it, and the reindeer are craving salt.

However, it is sort of nice to have these animals about, regardless of the mess and mischief.


However, we really do need to get that reindeer fence built as quickly as possible. At the moment, the reindeer antlers are still soft, as they are covered with velvet. But in the autumn, this will be shed, leaving sharp-points... just perfect for puncturing antenna tiles.

Have a nice weekend!

Photos: D. McKay-Bukowski

Grounded

The second ground connection has been made on the electrical supply to the site. This was done at the beginning of the month, prior to the connection of the main electrical connection.

Although we have had mains power on the site for some time, the high-capacity circuit to the RF-container had not yet been made.

Additional works and checks need to be carried out before that can be done.

Patch panels

This is what the patch panel in the RF-container now looks like. It is half-filled, as we are only deploying 48 tiles as part of the initial HBA installation. A further 49 tiles could be put in place for a second phase. These would then go into the top part of the panel (so, positions 00 to 48 are left free). The reason why 49 pairs have been left is because one of the existing HBA tile positions is not part of the international station layout. Therefore, there will be 49 new positions. It is certainly easier to put in a new cable set than to move one.

The team did a pretty neat job — arguably the second neatest of all LOFAR stations (as no-one can beat Dave King's work, of course). ;-)

The cabling starts from the bottom to make the deployment easier. By leaving the top cables free, this will greatly aid the installation of the second phase. However, to avoid confusion, we have re-labelled the part of the back panel that has been used.


This will help the ASTRON engineers who will complete the next part of the installation, which is cabling from the back of the patch panel to the digital signal processing electronics.

Cable testing

Although we've already tested the cables before installation, now that they are in place, we've done an additional check.

This new check is our 'loop back' test. In each antenna tile, the two cables (X- and Y-polarisation) are connected together with a barrel connector. This means that a signal can be sent out one cable, all the way out to the antenna, and then come back through the other cable to the RF-container.

This means that from the patch panel in the RF-container, we can efficiently test all the cables to make sure that none were damaged or incorrectly connected during the installation process.

In the photograph Juha Vierinen does the checks; everything was okay. The reason why it looks a bit gloomy in the container is that we do not have electricity there yet for lights and the back of the patch panel is in quite a shaded place.

Sea of cables

By the time the cabling work was complete, there seemed to be a lot of cables on the mausoleum tray.

Sea of cables

In fact, although it seems a lot, it really isn't that much compared to the total amount in the array.

Arttu Jutila waits for the next cable feed on the other side of the cables.

Visit from the project director

Although we have site engineers, site managers, and various other roles to ensure things get done... ultimately, this project is being directed by Professor Markku Lehtinen, from Sodankylä Geophysical Observatory.

On 3rd August 2011, Prof. Lehtinen visited the site to inspect the work that had been done.

Green to gold

Already the leaves are changing colour. Winter is definitely on its way!

We noticed the first yellow leaves at the end of the July, but now they are apparent everywhere.